U.S. patent number 5,403,881 [Application Number 08/141,459] was granted by the patent office on 1995-04-04 for room-temperature-curable composition.
This patent grant is currently assigned to Dow Corning Toray Silicone Co., Ltd.. Invention is credited to Tadashi Okawa, Shigeki Sugiyama, Shuji Yamada.
United States Patent |
5,403,881 |
Okawa , et al. |
April 4, 1995 |
Room-temperature-curable composition
Abstract
A room-temperature-curable composition is very storage stable
under seal at room temperature, cures to give a rubbery elastic
material with excellent physical properties, and is useful as a
sealant composition when polyoxyalkylene has at the terminals
groups of the formula ##STR1## of which one example of a
organosiloxane-modified polyoxyalkylene is ##STR2## in which Me is
methyl.
Inventors: |
Okawa; Tadashi (Chiba,
JP), Sugiyama; Shigeki (Chiba, JP), Yamada;
Shuji (Chiba, JP) |
Assignee: |
Dow Corning Toray Silicone Co.,
Ltd. (Tokyo, JP)
|
Family
ID: |
18359489 |
Appl.
No.: |
08/141,459 |
Filed: |
October 22, 1993 |
Foreign Application Priority Data
|
|
|
|
|
Nov 30, 1992 [JP] |
|
|
4-343174 |
|
Current U.S.
Class: |
524/261; 524/268;
524/425; 524/788; 528/34; 528/33; 525/403; 524/588 |
Current CPC
Class: |
C08G
65/336 (20130101); C08K 5/5419 (20130101); C08L
83/04 (20130101); C08L 83/12 (20130101); C07F
7/0838 (20130101); C09K 3/1018 (20130101); C08K
5/5419 (20130101); C08L 83/04 (20130101); C08L
83/12 (20130101); C08L 2666/44 (20130101) |
Current International
Class: |
C08G
65/336 (20060101); C08K 5/00 (20060101); C08L
83/12 (20060101); C09K 3/10 (20060101); C08L
83/00 (20060101); C08L 83/04 (20060101); C08K
5/5419 (20060101); C07F 7/00 (20060101); C07F
7/08 (20060101); C08G 65/00 (20060101); C08K
005/24 () |
Field of
Search: |
;524/261,268,425,588,788
;525/403 ;528/17,33,34 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
73998 |
|
Jun 1977 |
|
JP |
|
115456 |
|
Jul 1982 |
|
JP |
|
3-294355 |
|
Dec 1991 |
|
JP |
|
Primary Examiner: Bleutge; John C.
Assistant Examiner: Sweet; Mark D.
Attorney, Agent or Firm: Borrousch; Roger H.
Claims
That which is claimed is:
1. A room-temperature-curable composition comprising
(A) 100 weight parts of a organosiloxane-modified polyoxyalkylene
whose main chain is constituted of the unit with the formula --RO--
in which R is an alkylene group having 1 to 4 carbon atoms, and
that has the group with the following formula in molecular chain
terminal position ##STR12## in which R.sup.1 is a divalent
hydrocarbon group, R.sup. 2 is the hydrogen atom or a monovalent
hydrocarbon group, R.sup.3 and R.sup.4 are monovalent hydrocarbon
groups, X is a divalent organic group, a is 0, 1, or 2, m is a
number with a value of at least 1, and is 0 or 1;
(B) 0.1 to 50 weight parts of an Si.sub.1-20 silicon compound that
contains at least 2 silicon-bonded alkoxy groups in each
molecule;
(C) a condensation-reaction catalyst in a quantity sufficient to
cure the composition; and
(D) 0 to 250 weight parts of an inorganic filler.
2. The room-temperature-curable composition according to claim 1 in
which (B) is present in an amount of from 1 to 10 weight parts, (C)
is present in an amount of from 0.1 to 10 weight parts, and (D) is
present in an amount of from 10 to 200 weight parts.
3. The room-temperature-curable composition according to claim 1 in
which each R.sup.2, R.sup.3, and R.sup.4 is methyl, X is ethylene,
a is 3, and n is 0.
4. The room-temperature-curable composition according to claim 2 in
which each R.sup.2, R.sup.3 and R.sup.4 is methyl, X is ethylene, a
is 3 and n is 0.
5. The room-temperature-curable composition according to claim 1 in
which each R.sup.2, R.sup.3, and R.sup.4 is methyl, X is ethylene,
a is 2, and n is 0.
6. The room-temperature-curable composition according to claim 2 in
which each R.sup.2, R.sup.3, and R.sup.4 is methyl, X is ethylene,
a is 2, and n is 0.
7. The room-temperature-curable composition according to claim 3 in
which the catalyst of (C) is a titanium catalyst.
8. The room-temperature-curable composition according to claim 4 in
which the catalyst of (C) is a titanium catalyst.
9. The room-temperature-curable composition according to claim 5 in
which the catalyst of (C) is a titanium catalyst.
10. The room-temperature-curable composition according to claim 6
in which the catalyst of (C) is a titanium catalyst.
11. The room-temperature-curable composition according to claim 7
in which (B) is methyltrimethoxysilane and (D) is calcium
carbonate.
12. The room-temperature-curable composition according to claim 8
in which (B) is methyltrimethoxysilane and (D) is calcium
carbonate.
13. The room-temperature-curable composition according to claim 9
in which (B) is methyltrimethoxysilane and (D) is calcium
carbonate.
14. The room-temperature-curable composition according to claim 10
in which (B) is methyltrimethoxysilane and (D) is calcium
carbonate.
15. The room-temperature-curable composition according to claim 11
in which (C) is diisoproxytitanium bis(acetyl-acetone).
16. The room-temperature-curable composition according to claim 12
in which (C) is diisoproxytitanium bis(acetyl-acetone).
17. The room-temperature-curable composition according to claim 13
in which (C) is diisoproxytitanium bis(acetyl-acetone).
18. The room-temperature-curable composition according to claim 14
in which (C) is diisoproxytitanium bis(acetyl-acetone).
Description
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a room-temperature-curable
composition. More specifically, the present invention relates to a
room-temperature-curable composition that has an excellent storage
stability under seal at room temperature and that is useful as a
sealant composition.
2. Prior Art and Problem to Be Solved by the Invention
One example of a room-temperature-curable sealant composition is
the composition disclosed in Japanese Patent Application Laid Open
[Kokai or Unexamined] Number Sho 52-73998 [73,998/1977], published
Jun. 21, 1977. The base component in this composition is a polymer
that has a polyoxyalkylene main chain and silicon-bonded methoxy in
terminal position. A drawback to this room-temperature-curable
sealant composition is that its weathering resistance is inferior
to that of silicone sealant compositions.
Japanese Patent Application Laid Open Number Sho 57-115456
[115,456/1982 ], published Jul. 17, 1982, discloses a
room-temperature-curable composition whose base component is a
copolymer in which polyoxyalkylene is bonded across a divalent
organic group to organopolysiloxane having terminal-position
Si-bonded hydrolyzable groups. However, the copolymer that is the
base component of this composition contains a siloxane bond
adjacent to hydrolyzable group-bearing silicon and is therefore
very susceptible to attack by nucleophiles. As a result, the
room-temperature-curable composition based on this copolymer has a
poor storage stability under seal.
SUMMARY OF THE INVENTION
The inventors conducted extensive research in order to solve the
problem described above. As a result, with regard to a copolymer in
which polyoxyalkylene is bonded across a divalent organic group to
organopolysiloxane (or organosiloxane) having terminal- position
Si-bonded alkoxy groups, the inventors discovered that the
substitution of a divalent organic group for the oxygen atom in the
siloxane bond at the end of the organopolysiloxane (or
organosiloxane) chain yields a copolymer that can be formulated
into a room-temperature-curable composition having a substantially
improved storage stability under seal. The present invention was
developed based on this discovery.
The present invention takes as its object the introduction of a
room-temperature-curable composition that is very storage stable
under seal at room temperature and that cures to give a rubbery
elastic material with excellent physical properties.
This invention relates to a room-temperature-curable composition
comprising (A) 100 weight parts of a organosiloxane-modified
polyoxyalkylene that has a molecular weight of 500 to 16,000, whose
main chain is constituted of the unit with the formula --RO-- in
which R is an alkylene group having 1 to 4 carbon atoms, and that
has the group with the following formula in molecular chain
terminal position ##STR3## in which R.sup.1 is a divalent
hydrocarbon group, R.sup.2 is the hydrogen atom or a monovalent
hydrocarbon group, R.sup.3 and R.sup.4 are monovalent hydrocarbon
groups, X is a divalent organic group, a is 0, 1, or 2, m is a
number with a value of at least 1, and n is 0 or 1; (B) 0.1 to 50
weight parts of an Si.sub.1-20 silicon compound that contains at
least 2 silicon-bonded alkoxy groups in each molecule; (C) a
condensation-reaction catalyst in a quantity sufficient to cure the
composition; and (D) 0 to 250 weight parts of an inorganic
filler.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Component (A) is the main or base component of tile composition of
the present invention, and it is a organosiloxane-modified
polyoxyalkylene that has a main chain constituted of the --RO--
unit and that has the group with the following formula in molecular
chain terminal position: ##STR4## R is a C.sub.1 -C.sub.4 alkylene
group and is exemplified by methylene, ethylene, 1-methylethylene,
1-ethylethylene, and 1,1-dimethyl-ethylene. R.sup.1 in the
preceding formula is a divalent hydrocarbon group and is
exemplified by methylene, ethylene, propylene, and butylene.
R.sup.2 is the hydrogen atom or a monovalent hydrocarbon group, and
the latter is exemplified by alkyl groups such as methyl, ethyl,
and propyl; cycloalkyl groups such as cyclohexyl; aryl groups such
as phenyl, tolyl, and xylyl; and aralkyl groups such as benzyl and
phenethyl. R.sup.3 and R.sup.4 in each case are monovalent
hydrocarbon groups as defined for R.sup.2. The group X in the
preceding formula is a divalent organic group and is exemplified by
methylene, ethylene, propylene, butylene, phenylene, and
substituted phenylene. The subscripts in the preceding formula have
the following values: a=0, 1, or 2; m is a number with a value of
at least 1; and n =0 or 1. This component has a molecular weight of
500 to 16,000. Component (A) can be synthesized by an addition
reaction between SiH-containing organosiloxane or SiH-containing
organopolysiloxane with the following formula ##STR5## wherein
R.sup.3, R.sup.4, X, m, and a are defined as above, and
polyoxyalkylene (molecular weight=400 to 15,000) that contains in
each molecule in molecular chain terminal position at least 1.1
unsaturated groups with the formula ##STR6## wherein R.sup.2 is
defined as above.
Component (B) is an Si.sub.1-20 silicon compound that contains at
least 2 silicon-bonded alkoxy groups in each molecule. Component
(B) is used (i) to adjust properties such as the tensile strength
and elongation in the cured product afforded by the composition of
the present invention and (ii) to improve the adherence of the
cured product. Component (B) is exemplified by silanes such
methyltrimethoxysilane, vinyltrimethoxysilane,
phenyltrimethoxysilane, tetramethoxysilane,
gamma-methacryloxypropyltrimethoxysilane,
gamma-glycidoxypropyl-trimethoxysilane,
gamma-aminopropyltrimethoxysilane, and so forth. Component (B) is
also exemplified by branched, cyclic, and linear Si.sub.1-20
silicon compounds that contain at least two silicon-bonded alkoxy
groups in each molecule.
Component (B) is added to the composition at 0.1 to 50 weight parts
per 100 weight parts component (A) and preferably at 1 to 10 weight
parts per 100 weight parts component (A) .
Operable for the condensation-reaction catalyst comprising
component (C) are the known silanol condensation-reaction catalysts
including titanium catalysts such as alkyl titanate esters;
organosilicon titanates; and titanium chelate compounds such as
diisopropoxytitanium bis(acetylacetone); metal carboxylates such as
tin octylate, dibutyltin dilaurate, dibutyltin diacetate, and
dibutyltin phthalate; and other acid catalysts and base
catalysts.
Component (C) should be added to the composition in a quantity
sufficient to effect curing of the composition of the present
invention. It is added, in general, at 0.1 to 20 weight parts per
100 weight parts component (A) and is preferably added at 0.1 to 10
weight parts per 100 weight parts component (A) .
The inorganic filler comprising component (D) is used on an
optional basis to improve various physical properties of the
composition of the present invention. Operable fillers are
exemplified by known inorganic fillers such as fumed silica,
precipitated silica, quartz powder, carbon black, calcium
carbonate, diatomaceous earth, clay, talc, titanium oxide, alumina,
bentonite, zinc oxide, ferric oxide, active zinc white, shirasu
balloons, asbestos, glass fiber, and so forth.
Component (D) is added at 0 to 250 weight parts per 100 weight
parts component (A) and preferably at 10 to 200 weight parts per
100 weight parts component (A).
The composition of the present invention is prepared by mixing the
specified quantities of components (A) through (C) or (A) through
(D) as described hereinbefore by a known mixing means. In addition
to the preceding components, the composition of the present
invention may also contain the various additives known in the art,
for example, plasticizers, colorants such as pigments and so forth,
heat stabilizers, cold- resistance improvers, flame retardants,
thixotropy agents, dehydrating agents, antimicrobials, adhesion
promoters, and so forth.
The composition of the present invention as described hereinbefore
has an excellent storage stability at room temperature under seal.
Moreover, this composition cures upon contact with moisture to
yield a rubbery elastic cured material that exhibits an excellent
weathering resistance. The composition of the present invention is
therefore very useful as a sealant composition for buildings,
ships, automobiles, roads, and so forth.
The present invention will be explained below in greater detail
through working examples, in which parts indicates weight
parts.
REFERENCE EXAMPLE 1
138.5 g (1013.5 millimoles) 1,1,3,3-tetramethyldisiloxane was mixed
with a platinum/1,3-divinyltetramethyldisiloxane complex so as to
give 20 ppm platinum metal based on the total weight of the
reaction mixture, and the mixture was heated to 80.degree. C. 50 g
(337.8 millimoles) vinyltrimethoxysilane was dripped into the
mixture, and heating under reflux was continued for an additional 1
hour after tile completion of this addition. The reaction mixture
was then sampled and analyzed by gas chromatography (GLC): the
vinyltrimethoxysilane peak had disappeared, which confirmed
completion of the reaction. After the excess
1,1,3,3-tetramethyldisiloxane had been distilled out by heating at
ambient pressure, vacuum distillation yielded 62.1 g of a fraction
at 65.5.degree. C.69.degree. C./133.3 Pa. The results of infrared
absorption spectral analysis (IR) and nuclear magnetic resonance
analysis (NMR) confirmed this fraction to be organosiloxane with
the following structural formula. ##STR7##
REFERENCE EXAMPLE 2
The following were mixed and heated to 80.degree. C.: 100 g (33.3
millimoles) polyoxypropylene (average molecular weight =3,000)
bearing the allyloxy group at both terminals, 100 mL toluene, and
sufficient platinum/1,3- divinyltetramethyldisiloxane complex to
give 20 ppm platinum metal based on the total weight of the
reaction mixture. 19.7 g (70.0 millimoles) of the organosiloxane
synthesized in Reference Example 1 was then dripped into the
mixture, and heating under reflux was continued for an additional 3
hours after the completion of this addition. The reaction mixture
was then sampled and analyzed by NMR: the vinyl group absorption
had disappeared, which confirmed completion of the reaction.
Removal of the low boilers by vacuum distillation with heating
yielded 116.9 g of a polymer. The results of IR and NMR analyses
confirmed this polymer to be organosiloxane-modified
polyoxypropylene with tile following structural formula.
##STR8##
REFERENCE EXAMPLE 3
42.8 g organosiloxane was prepared as in Reference Example 1, but
in this case using 90.0 g (668.2 millimoles)
1,1,3,3-tetramethyldisiloxane and also replacing the
vinyltrimethoxysilane with 30.0 g (222.7 millimoles)
vinylmethyldimethoxysilane. This organosiloxane was confirmed by IR
and NMR analyses to have the following structural formula.
##STR9##
REFERENCE EXAMPLE 4
116.8 g, polymer was prepared as in Reference Example 2, but in
this case using 18.62 g (70.0 millimoles) of the organosiloxane
synthesized in Reference Example 3 in place of the organosiloxane
synthesized in Reference Example 1. The results of IR and NMR
analyses confirmed this polymer to be organosiloxane-modified
polyoxypropylene with the following structural formula.
##STR10##
116.8 g polymer was prepared as in Reference Example 2, but in this
case using 18.9 g (70.0 millimoles)
1,1,3,3-tetramethyl-5,5,5-trimethoxytrisiloxane in place of the
organosiloxane synthesized in Reference Example 1. The results of
IR and NMR analyses confirmed this polymer to be
organosiloxane-modified polyoxypropylene with the following
structural formula. ##STR11##
EXAMPLE 1
A room-temperature-curable composition was prepared by mixing the
following: 100 parts of the organosiloxane-modified
polyoxypropylene prepared in Reference Example 2,150 parts
precipitated calcium carbonate, 5 parts methyltrimethoxysilane, and
2 parts diisopropoxytitanium bis(acetylacetone). This composition
was filled and sealed into aluminum tubes. The composition was then
discharged from a tube, molded into a 2 mm-thick sheet, and cured
in a 20.degree. C./60% RH ambient. After 7 days the physical
properties of the cured product were measured in accordance with
JIS K 6301. In addition, a composition-filled tube was held in a
50.degree. C. oven for 8 weeks, and the composition was then cured
as above and the physical properties of the cured material were
measured as above. The measurement results were as reported in
Table 1. The measurement results confirmed that this composition
had an excellent storage stability under seal.
EXAMPLE 2
A room-temperature-curable composition was prepared as in Example
1, but in this case using the organosiloxane-modified
polyoxypropylene synthesized in Reference Example 4 in place of the
organosiloxane-modified polyoxypropylene synthesized in Reference
Example 2 that was used in Example 1. The physical properties of
this composition were measured as in Example 1, and these results
were as reported in Table 1. These measurement results confirmed
that this composition exhibited an excellent storage stability
under seal.
COMPARISON EXAMPLE 1
A room-temperature-curable composition was prepared as in Example
1, but in this case using the organosiloxane-modified
polyoxypropylene synthesized in Reference Example 5 in place of the
organosiloxane-modified polyoxypropylene synthesized in Reference
Example 2 that was used in Example 1. The physical properties of
this composition were measured as in Example 1, and these results
were as reported in Table 1. These measurement results confirmed
that tile instant composition exhibited a storage stability under
seal that was substantially inferior to that of the compositions in
Example 1 and Example 2.
TABLE 1 ______________________________________ TENSILE HARDNESS
STRENGTH ELONGA- (JIS A) (kg/cm.sup.2) TION (%) After 8 After 8
After 8 Initial weeks Initial weeks Initial weeks
______________________________________ Example 1 50 45 24 19 400
380 Example 2 39 35 20 16 300 280 Comp. 46 9 21 3 300 25 Example 1
______________________________________
EFFECTS OF THE INVENTION
The room-temperature-curable composition of the present invention
is characterized by its excellent storage stability under seal at
room temperature and by its ability to cure into a rubbery elastic
material with excellent physical properties.
* * * * *